


Not So Black and White

by Moit



Category: Teen Wolf (TV)
Genre: Alternate Universe - Always a Different Sex, Cunnilingus, F/M, Female Stiles Stilinski, First Time, Genderplay, Het, Menstrual Sex, Menstruation, Menstruation Kink, Sex, Smut
Language: English
Status: Completed
Published: 2013-11-24
Updated: 2013-11-24
Packaged: 2018-01-02 13:47:10
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings, Underage
Chapters: 1
Words: 3,211
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1057502
Author URL: https://archiveofourown.org/users/Moit/pseuds/Moit
Summary: <blockquote class="userstuff">
              <p>Always-a-girl!Stiles stays home from school because she gets her period for the first time in years and Derek shows up asking why she smells like blood. Unapologetic smut ensues.</p>
            </blockquote>





	Not So Black and White

**Author's Note:**

> This is set sometime during season one, but that's not terribly important. Basically, it's just smut.
> 
> Spoilery trigger warning at the end.

Stiles had been a tomboy all of her life. She wore t-shirts and jeans and played with matchbox cars, and her best friend was a boy. After the death of her mother, it was easier for her to cope by hiding behind a buzz cut and an androgynous nickname. After Scott was bitten by Peter, however, Stiles' world began to unravel again. The stress of having a werewolf for a best friend and the trouble they had been getting into was beginning to affect Stiles for the worst, and the increased dose of Adderall she was on was starting to interact badly with the birth control she was on, giving her migraines. Her nurse suggested taking her off the pill temporarily, just to see if that helped with the migraines. 

Naturally, that meant that her next period was bad enough to keep her out of school. Her father had to work, so Stiles was upstairs in her bed wearing her favorite batman pajamas with a heat pack on her lower stomach in an effort to alleviate the cramps. She had already taken multiple doses of Tylenol, but nothing seemed to be working. 

In the middle of a Babylon 5 marathon she was watching in an effort to keep her mind off the pain in her uterus, Derek crawled through her window. If ever there was a time Stiles wished she had locked the damn thing, this was it. 

"I saw the Jeep out front. Why aren't you in school today?" 

Stiles exhaled slowly and kept her eyes on the television as she fought to control her heartbeat. "I'm sick. Isn't it obvious? What are you doing here, anyway? Don't you think it's a little creepy that you just 'happened' to drive past my house?" 

Derek shrugged one leather-clad shoulder. He glanced around the room as if looking for signs of sickness. His nose twitched and he arched an eyebrow. 

Stiles' heart sank. 

"Stiles, why do you smell like blood?" he asked, scenting the air more obviously. 

"I--I don't--Derek, really--It's just--" She didn't get to a full sentence because Derek was all of a sudden dragging the blankets off her body. He braced his hands against the mattress on either side of her and began scenting to find the source of the blood. The closer he got to the origin, the harder Stiles' heart beat. She knew it was time to come clean. "Derek, I have a confession to make," she all-but squeaked. 

The werewolf paused with his head above her thigh, nose twitching with interest. 

"I'm," she licked her suddenly dry lips nervously, "I'm actually a girl. I just never really stop anyone when they assume I'm a guy. Surprise?" she said, sounding much more unsure of herself than she ever had. 

What followed seemed like an eternity of silence, during which Stiles thought her heart would crack and split open into multiple pieces. Practically since the day they met, she and Derek had been dancing around one another so much that the others were all-but taking bets on how long it would take them to get together. This would surely prevent that from ever happening. 

Derek cocked his head to the side like an interested puppy. "You're on your period." 

Stiles stared at him. "Did you hear anything I just said? I'm not a dude. I have boobs!" She rubbed her hands over her close-cropped haircut in frustration. "I've been lying to you, Derek, and getting away with it." Irritated and suddenly too hot, she yanked the heat pack off her body and dropped it on the floor.

"Stiles," Derek said, sitting back on his haunches and placing one of his large hands over the entirety of her hip. His thumb began rubbing a distracting pattern over the slip of skin between her top and bottoms. His skin felt even hotter than the heat pack she'd just removed. "I'm not going to like you any more or less than I did yesterday just because you have different plumbing." He lifted himself back up onto his hands and knees so that he could lean down close enough to kiss her. "And the scent of your heat is driving me kind of crazy right now." 

"I'm not in heat, you loser. I'm just on my rag," Stiles said, pushing at Derek's shoulder ineffectively. 

"My wolf doesn't know the difference." Derek's breath was a hot fog over her face and Stiles felt a gush of wet between her legs that was absolutely not blood. 

"I've a virgin," Stiles whispered meekly against Derek's lips. 

"I'll be gentle." 

Stiles' breath caught as Derek's hands moved to the buttons of her pajama top. He allowed the fabric to remain where it fell, only revealing a slip of pale skin from her collarbone, down the valley between her breasts. As the cool air of the room hit her heated skin, Stiles' felt her nipples perk in response. Derek's gaze flicked up to her eyes briefly, as if asking for permission. She sucked her lower lip into her mouth and nodded once, sharply. 

The fabric of her black and yellow Batman pajamas parted under Derek's fingertips, the calloused texture grazing her nipples. His eyes met hers again, and this time he kept her gaze as his thumbs encouraged her nipples into hard little points. Stiles couldn't stop the soft little sigh that escaped her lips as Derek worked on her breasts. One of her hands came up to clutch his shoulder, blunt nails digging into the fabric of his leather jacket. 

"God, why are you even still wearing this thing?" she asked, pushing it off his shoulders with both hands. 

Derek let go of Stiles' nipples long enough to shrug out of his jacket and toss it to the floor. When he returned, it was his mouth instead. This time, Stiles did squeal, digging her heels into the bed. 

"Shh," Derek mumbled against the soft skin of her breast, sliding one hand up her body to press his first two fingers against her lips. "Someone might hear you." 

Stiles' groan was cut short when one of Derek's fingertips slipped into her mouth. She latched on instantly, laving the pad of the finger with her tongue as she mimicked motions of the mouth on her breast. 

Derek released the nipple in his mouth, blowing on it softly. When Stiles wiggled in response, he took the nub softly between his blunt human teeth and looked up and her with a cheeky grin. Reaching up, Stiles wrapped her long fingers around Derek's wrist. She pulled his finger out of her mouth so she could say, "Cute, Fido." 

Derek's growl turned throaty and lupine. He turned his attention to her other nipple, eliciting more noises of pleasure from the girl's throat. Stiles felt it all the way down to her core. 

"Come on, Hale, I never had you pegged for the slow and patient type. What happened to all that _grr_ you had when we met?" 

A moment later, Derek was kissing her. It was her first kiss (kissing Scott when they were 8 didn't count) and it was a good thing she was laying down, or else Stiles might have fallen. Derek's hand cupped her cheek as his tongue mapped the inside of her mouth. Stiles rolled her hips into his body and-- _Whoa, that's a dick_ , her pleasure-addled brain supplied. Instead of freaking her out, it just made her wrap a leg around Derek's hip, desperate for more friction. 

"Is that growly enough for you?" Derek asked, burying his nose into the skin behind Stiles' ear, and his voice was all wolf. 

"Getting there," Stiles whimpered, lifting her chin to reveal more of her throat. The feeling of his stubble against her skin was almost enough to make her lose it. She slid one hand into the back pocket of his jeans in an attempt to press his hips harder into hers. 

"I want to eat your pussy," Derek whispered, licking a wet stripe underneath Stiles' jaw. 

Another rush of wetness soaked Stiles' panties even as her stomach clenched with anxiety. "I don't know about that," she said, squirming beneath Derek's touch, but the werewolf wasn't listening. He was too busy trailing kisses down her chest, over her quivering belly, moving ever closer to the apex between her legs. "Derek," she tried again, patting him insistently on the shoulder as his fingers inched the waistband of her bottoms lower on her hips.

He paused to raise an eyebrow when he had her bottoms low enough to reveal her Robin briefs. "Really, Stiles?"

"They go with the outfit," she frowned. 

Derek just shook his head and pulled the fabric down and off her legs. 

"Wait," Stiles said, reaching out to stop Derek before he could lay his hands on her underwear. "Let me just . . . " She disentangled herself from his body and swung her long legs over the edge of the bed. 

"Where are you going?" Derek asked, sitting back on his heels again. 

"You'll see," Stiles called over her shoulder as she disappeared into the bathroom. She appeared a moment later nude but for the folded towel held strategically in front of her body. Derek's eyes drank in the sight, as evidenced by the bulge in his jeans. Stiles kept her own eyes fixed firmly on a point that was _not_ Derek, painfully aware that her cheeks were on fire. "Get up a second," she said, shaking the dark blue towel out. 

Still staring unabashedly, Derek stood up and waited patiently while Stiles laid the towel across the bed. "Okay," she said, laying back down, but modestly keeping her knees together. "I don't know about you, but I don't like cleaning blood out of my sheets." She wiggled a bit until her hips were centered over the towel. 

Derek crossed his arms over his body and pulled his t-shirt off in one smooth motion. The muscles in his arms and chest rippled with preternatural strength. Stiles had to stop herself from groaning at the sight. Instead of crawling back on top of her, however, Derek settled himself against her side, his fingertips playing along the soft skin of her thigh. To keep up appearances, she did not shave any part of her body except for her bikini line, which nobody would see. Derek's eyes did not, as she would have assumed, zero in on the one place she wanted him most, but it allowed her body to relax by fractions. 

"I'm not going to hurt you," Derek said gently, and with each stroke of his hand, he was gently encouraging her thighs to part until the knee closest to him fell to the bed, revealing her to his gaze. "You are so beautiful," he said, but his eyes were trained on her face. 

"Stop it," Stiles giggled, smearing her grin into the pillow beneath her head. "I already said yes; you don't need to talk me into it." 

"I'm not trying to talk you into anything." Derek's eyes remained locked on hers as he placed his hands on the inside of her thighs and lowered his head. His gaze flicked downward and he inhaled deeply through his nose. When he looked back up, his eyes were bright blue. Stiles didn't even try to stop the noise that came out of her throat.

At first Derek didn't even touch her; he just breathed against the sensitive folds, making her writhe and squirm with frustration. Not even when she fisted his hair in both hands did he give in. If anything, it seemed to inspire more teasing. 

Finally, when Stiles thought she might go mad from the touch of Derek's hands, his mouth, everywhere but at her core, he licked a long, wet strip between her pussy lips and over her clit. Any embarrassing thoughts she had about being on her period were immediately thrown out the window. Her world narrowed down to the throbbing between her legs and Derek's mouth. 

When she thought she could go just from the feeling of Derek's tongue, he pulled away and slid one long finger inside of her. Stiles' mouth fell open in a silent gasp. Her hips swiveled wantonly, begging for more. 

Derek lowered his face to her clit once again, bathing the tiny bundle of nerves in saliva. It didn't take Stiles much longer to reach her peak. She came, clutching tightly to Derek's hair with both hands. Had he been human, he might have objected more. He didn't pull away until the tremors in Stiles' body subsided. When he went to kiss her, however, she turned her head. 

"That's gross." 

"It's completely natural." He did not, she noticed, have any . . . evidence on his face. 

"It's completely natural to both bleed from the vagina and to perform oral sex. It is not natural, however, to put one's menstrual blood in one's mouth." She raised her eyebrows in challenge.

Derek just shook his head and chuckled. "You are something else," he said, settling for sucking a mark into her shoulder instead. 

"How about you?" Stiles said, tucking her fingertips into the waistband of the jeans he still wore. 

"Are you up for it?" Derek slid his hand back down between Stiles' legs, pulling a gasp from her throat as he stroked her oversensitive skin. 

"As long as you promise not to knot me."

Derek's expression morphed into one of confusion. 

"Kidding!" Stiles said. "Don't you ever use the Internet? Some people are into that sort of thing."

"I don't even want to know," Derek said, shaking his head. Since there was no graceful way around it, he stood up from the bed again to shuck his jeans and boxers. When he returned, Stiles was treated to an eyeful of nude, adult male werewolf. Her body shivered in anticipation. "Are you cold?" Derek asked. 

"I won't be in a minute," Stiles said, reaching out to encourage Derek closer. He settled into the v between her legs, hard cock resting against her hip. "Did you bring a condom?"

"I'm a werewolf," was Derek's immediate response. 

"That's fantastic." Stiles rolled her eyes. "Did the werewolf bring a condom?"

"Stiles, I can't catch or carry a disease. I'm clean." 

"I could still get pregnant." 

"But you're on your period." 

"But I still could." Stiles stared into Derek's eyes; neither of them seemed prepared to back down, and Stiles wasn't inclined to drive down to the Walgreens right this second. "If I do get pregnant, promise me you'll pay for half the abortion," she said seriously. 

"Stiles," Derek started, but she cut him off. 

"Promise me, or I'm kicking you out."

"Fine," Derek said, cupping her face in his hand and running his thumb over her cheekbone, "if by some miracle I manage to impregnate you, I will do the right thing and pay for the abortion." 

"Thank you," Stiles said, leaning up to kiss his nose. "You may proceed to deflower me." 

Derek reached down between her legs to ensure that she was still sufficiently wet before taking himself in hand and pressing forward. At Stiles' soft gasp, he stopped, worried eyes trained on her face. "Did I hurt you?" 

"You're just a lot bigger than . . . I can't say than I was expecting, because I certainly wasn't expecting this, but definitely bigger than anything I've ever imagined." 

"I'll go slow," Derek promised. He paused after nearly every millimeter, just to ensure Stiles was still with him. Her eyes were closed tightly and he could see tears leaking out of them at the corner, but still she urged him on. When he was fully seated, he buried his face in the juncture between her neck and shoulder. "You are so tight." 

"Make no mistake, Sour Wolf, this fucking hurts," Stiles sighed, wiping at the tears in her eyes. 

"Do you want to stop?" Derek asked seriously. 

"No." She drew her knees up on either side of Derek's body, bracketing him in and changing the angle slightly. "Rumor has it that it gets better." 

"That's what I hear." Derek rubbed a hand over her shorn hair. "Just tell me when." 

After several tense, silent minutes, Stiles nodded. "Okay." 

Derek lifted himself up onto his elbows. He watched Stiles' face as he slowly pulled out and pushed back in again. Her eyes screwed up tightly, but her mouth fell open with a soft sigh. "Yeah?" Derek asked rhetorically. 

Stiles hummed in response. She hooked a hand around the back of Derek's neck and dragged him back down for a kiss. Her hips began to move of their own accord, meeting Derek's at every thrust. 

"Do you want to try a different position?" Derek asked after a beat. 

"I'm good," Stiles replied, sliding her palm down the sweaty expanse of Derek's chest. 

"You sure?" Derek asked. "I could maybe do you from behind? Or put you on top?" He reached for her knee, lifting it higher to drive himself deeper inside her body. 

"Thanks, but I really don't like the idea of you treating my breasts like handlebars." 

Derek was so stunned he could only stare at her. Stiles shut his jaw with a soft click. "Don't do that. You'll catch flies." 

"You are one of a kind." 

"So I'm told." Stiles linked her ankles around Derek's back. "How long are you planning to go for? I mean, I'm not complaining, but I don't think I'm a marathon sex kind of girl." 

"I was kind of hoping to get you off again," Derek said, snaking a hand between them to rub against Stiles' clit. 

"Thanks, but no," Stiles said, pulling his hand away gently. "I'm just a bit over-sensitized right now." 

"We'll work towards that next time." Stiles didn't have a chance to reply because Derek was soon moving at a pace fast enough to take her breath away. It was all she could do to hold on. 

Suddenly, he pulled out and began jacking himself furiously. He came with a harsh cry onto the skin of Stiles' belly. 

"Wow, dude," she said, looking from the mess on her stomach to Derek's face, "gross." 

Derek just shook his head and chuckled. "Well, it was either that or inside you, and we already discussed how you feel about being cast on 16 and Pregnant." 

"Wait," Stiles said, her expression serious, "Did Derek Hale just make a _joke_? Mark this day down on your calendar, ladies and gentlemen." 

Derek leaned down and placed a gentle kiss on Stiles' lips. "Do you want to shower? I'm sure you don't want to lay around covered in my spunk all day." 

"I don't know, it has a sort of je ne sais quois quality about it," she said, while dragging herself up off the bed. A red-tinged slick of wetness began to slide down her inner thigh. "On second thought, I do need to . . . tend to myself." She paused at the door to the bathroom, throwing a glance over her shoulder. "Are you coming?"

Grinning, Derek stalked forward, looking like so much more _man_ than he had moments before. 

After a joint shower, Stiles was snuggled up in her batman pajamas with Derek, a werewolf furnace, at her back. No medication could compete with him.

**Author's Note:**

> TW: In conversation, Derek agrees to pay for an abortion in the event that Stiles gets pregnant.


End file.
